This application relates to a cover plate for a turbine rotor disk in a gas turbine engine, wherein the cover plate has an enclosed pumping chamber for moving a cooling air from a central location to a cooling passage for delivering the air to a turbine blade.
Gas turbine engines are known, and typically include a compressor for delivering air downstream to a combustion section. The air is mixed with fuel and burned in the combustion section, and the products of combustion move downstream over turbine rotors, driving the turbine rotors to rotate. The turbine rotors typically include a rotor disk, and a plurality of circumferentially spaced removable turbine blades. Since the rotor disk and turbine blades are subject to extreme temperatures, cooling air is typically delivered to these components to cool them.
Some of the cooling air is delivered from a central location in the rotor disk radially outwardly to the interior of a disk slot in the rotor disk. The disk slot receives a root section from the turbine blade. The air then communicates into cooling air passages in the turbine blade.
To seal the cooling passages, cover plates are typically attached to the rotor disk. Cover plates that form a small gap by following the contour of the disk create a boundary layer effect that pumps cooling air from a central location to the radially outward location when the cover plate and rotor rotate. The cover plates have been formed with internal fins which increases the pumping effectiveness. However, these fins have been somewhat ineffective at locations where the rotor may bend away from the cover plate. As an example, a central web of the rotor may be thinner than radially inner and outer portions of the rotor. This may be due to a desire to reduce the weight of the rotor, or for other reasons. In the past, the cover plate has been ineffective in moving cooling air when it is spaced from this central web.
On the other hand, a cover plate that it is formed to follow the central web of the rotor, might well cause stress concentrations which would require the cover plate to be unduly large and heavy.